Butyric aldehyde oxidation

Published work on the oxidation of aldehydes higher than propion-aldehyde at intermediate and high temperatures is not yet extensive, although Baldwin et al, [109] have shown that the behaviour of z-butyr-aldehyde is similar to that of propionaldehyde. 

The vapor which it gives ofif at ordinary temperatures forms a white cloud when it comes in contact with a glass rod moistened with HCl, as does NH,. It forms salts which crystallize with difficulty. Cl and Br combine with it to form crystallizable compounds I in alcoholic solution forms a brown precipitate in alcoholic solutions of coniine, which is soluble without color in an excess. Oxidizing agents attack it with production of butyric acid (see below). The iodides of ethyl and methyl combine with it to form iodides of ethyl and methjl-conium. It has been obtained synthetically by first allowing butyric aldehyde and an alcoholic solution of ammonia to remain some months in contact at 30 (86 F ), when dibutyimldine is formed. 

BUTYRAL BUTYRIC ALDEHYDE (123-72-8) Forms explosive mixture with air (flash point — 10°F/—12°C). Can form explosive peroxides with air polymerization may occur. Incompatible with strong oxidizers, strong acids (with elevated temperature and pressure), caustics, amines, ammonia. 

Cyclohexene oxide in pentane added dropwise to B-iododiisopinocampheylborane in the same solvent at —100° under N2, stirred for 0.5 h, quenched with excess butyr-aldehyde, allowed to warm gradually to room temp., stirred for a further 1 h, diluted with pentane, treated with diethanolamine in THF, and stirring continued for 0.5 h (lR,2R)-(-)-2-iodocyclohexanol. Y 89% (e.e. 91%). Reaction is independent of solvent or molarity. F.e. incl. bromohydrins s. N.N. Joshi et al., J. Am. Chem. Soc. 110,6246-8 (1988) 1,2-chlorhydrins with chiral chloroaluminate or alkoxyaluminium chlorides cf. Y. Naruse et al. Tetrahedron 44, 4747-56 (1988). 

Thus, -butyl [71-36-3] [71-36-3] and isobutyl alcohol [78-83-1] [78-83-1] are obtained by hydrogenation of their respective aldehydes and butyric and isobutyric acid are produced by oxidation. 

Several species of bacteria under suitable conditions cause / -butyraldehyde to undergo the Canni22aro reaction (simultaneous oxidation and reduction to butyric acid and butanol, respectively) this reaction can also be cataly2ed by Raney nickel (7). The direct formation of butyl butyrate [109-21 -7] or isobutyl isobutyrate [97-85-8](Vish.ch.erik.o reaction) from the corresponding aldehyde takes place rapidly with aluminum ethylate or aluminum butyrate as catalyst (8). An essentially quantitative yield of butyl butyrate, CgH2 02, from butyraldehyde has been reported usiag a mthenium catalyst, RuH,[P(C,H,)3], (9). 

Oxidation of Aldehydes to Carboxylic Acids Investigated in Micro Reactors Cas/liquid reaction 26 [CL 26) Homc eneously catalyzed oxidation of butyraldehyde to butyric acid... 

Taylor and Flood could show that polystyrene-bound phenylselenic acid in the presence of TBHP can catalyze the oxidation of benzylic alcohols to ketones or aldehydes in a biphasic system (polymer-TBHP/alcohol in CCI4) in good yields (69-100%) (Scheme 117) °. No overoxidation of aldehydes to carboxylic acids was observed and unactivated allylic alcohols or aliphatic alcohols were unreactive under these conditions. In 1999, Berkessel and Sklorz presented a manganese-catalyzed method for the oxidation of primary and secondary alcohols to the corresponding carboxylic acids and ketones (Scheme 118). The authors employed the Mn-tmtacn complex (Mn/168a) in the presence of sodium ascorbate as very efficient cocatalyst and 30% H2O2 as oxidant to oxidize 1-butanol to butyric acid and 2-pentanol to 2-pentanone in yields of 90% and 97%, respectively. This catalytic system shows very good catalytic activity, as can be seen from the fact that for the oxidation of 2-pentanol as little as 0.03% of the catalyst is necessary to obtain the ketone in excellent yield. 

If butyric acid is electrolyzed with perchlorate, according to the procedure of Hofer and Moest,2 hexane is the preponderating product there are also obtained propyl alcohol and its oxidation product, propionic aldehyde ... 

In a more recent approach (Scheme 11), Schin-zer solved the problem of the C4-C5 retro-aldol reaction with Braun s (S)-HYTRA (51) [44] by replacing the keto group in /(-ketoaldehyde 49 with a C=C double bond cf. 52, derived in four steps from ethyl-2-bromo-Ao-butyrate and 3-pentanone in 13% overall yield). The thus formed intermediate 53 is later deprotected and cleaved oxidatively to give the desired C5 ketone 7 in 52 % yield and 96 % ee from aldehyde 52 [22]. 

The oxidation of aliphatic alcohols in benzene or petroleum ether with /ert-butyl chromate at 1-2 °C for 6 h leads to mixtures of aldehydes, acids, and their esters. Butanol gives 30% of butanal, 27% of butyric acid, and 36% of butyl butyrate [677], Also, electrolysis of aliphatic alcohols on platinum or carbon electrodes in aqueous potassium iodide at room temperature results in 80-83% yields of the corresponding esters [121]. 

The essence of citrus flavor is a complex mixture of volatile alcohols, aldehydes, esters, hydrocarbons, ketones and oxides. Alcohols are the largest class and ethanol is the main organic constituent of the essence. Esters and aldehydes are considered to contribute most to the characteristic flavor and aroma. In these two classes ethyl butyrate and acetaldehyde were shown to be important components of high quality orange juice (1). 

Although ethanol is dehydrogenated to acetaldehyde in the presence of zinc oxide at temperatures of 300° to 400° C. and atmospheric pressure, no aldehyde results when the reaction is conducted under sufficient hydrogen pressure. Instead a complex mixture including esters of acetic, butyric, and caproic acids and alcohols up to and higher than octyl is formed.01 Condensation reactions of acetaldehyde are used to account for the formation of these compounds but no definite proof has as yet been advanced to establish the mechanisms. 

Butanol is vaporized and passed over a copper catalyst08 for the purpose of dehydrogenation to aldehyde. The aldehyde is separated from the products by fractionation and oxidized to butyric acid in the liquid state with air or oxygen in the presence of a catalyst such as manganese butyrate. With a copper tube yi inch in diameter and packed for 26 inches with fused cupric oxide 240 cc. of butanol per hour may be treated with a 75 per cent conversion per pass.04 At temperatures of 220° to 280° C. the yields of aldehyde are good. At 370° C. only about one-sixth of the aldehyde that forms is decomposed. 

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